The present invention is directed to a light waveguide switch having a switch tongue which coacts with a carrier part, with both the switch tongue and part being composed of flat material and the tongue being deflectible transversely relative to its longitudinal length. The tongue and carrier are mounted on a base member which forms a seating surface for the switch tongue when it is in the first of two switch positions and also supports an adjustable stop which determines the position of the switch tongue while in the second switch position.
A light waveguide switch is disclosed in U.S. patent application Ser. No. 706,233, filed Feb. 27, 1985, which claims priority from German Application No. P 31 38 686. In this light waveguide switch, a switch tongue and carrier part are composed of a spring sheet, which sheet, on an upper surface, carries a fiber-shaped light waveguide for both the tongue and the carrier part and on an under surface also has a second fibershaped light waveguide. As illustrated in this application, the switch tongue and carrier part are interconnected as one piece of the sheet and are separated from each other by at least one cutout portion. This sheet-like plate is secured onto a highly precision, planar surface of a base member which has a groove for the light waveguides secured to the tongue. The planar surface forms a seating surface or stop surface for a first switch position of the tongue of the switch. In the first switch position, the end faces of the light waveguides secured to the two surfaces of the tongue will be positioned opposite and in alignment with the two waveguides secured to the carrier. Since the carrier and tongue are formed of the same plate which has the same thickness, the alignment is down to the micrometer range.
In a second switch position, the switch tongue is deflected transversely relative to the running direction, and the end face of the lower light waveguide of the switch tongue is moved to be in alignment with the upper light waveguide on the carrier plate and to be aligned therewith. To this end, it is necessary to provide a height precision stop for the switch tongue in the second position, which limits the movement of the switch tongue so that the end face of the light waveguides to be coupled in the second switch position are exactly aligned opposite one another. To this end, published German Application 33 35 679 discloses that a trapezoidal spring clip having ends supported on either the sheet forming the tongue and carrier or on the base member is provided on both sides of the switch tongue, and each of these have a laterally extending projection, which will engage the tongue as it moves toward the second position. Due to the resilient nature of the clip, the position of this lateral projection can be adjusted with the assistance of a screw fastener that extends through the cross member and is connected to the base member. If the switch tongue has outwardly extending ears, they are the ones that engage these protrusions or projections, and the projections form the second stop, against which the switch tongue is supported in its second switch position. However, two adjustment elements, namely the two screws, one for each spring clip, must be adjusted for adjusting the position of the switch tongue in the second switch position. In addition, the position of the two stops, which differs in height, must also be avoided, because then the switch tongue would only be initially supported against one of the two stops and would then have a tendency to pivot on the engaged stop to pivot the tongue around its longitudinal axis out of the planar position.